When native Washingtonian and investment broker Patrick C. Ryan was attending high school here, and learning for the first time about money and banking, "The Riggs" was a symbol to him.

"Riggs Bank was always something you looked up to, really a rock, across from the Treasury and the White House," Ryan recalled last week, as he discussed one of the biggest bombshells ever to hit Washington business -- a hostile bid for control of Riggs by self-confident millionaire Joe L. Allbritton, former owner of The Washington Star.

Riggs is one of the oldest and best-known names in the capital of the United States -- as a search of graveyard markers in the area would show. Virtually from the bank's 1836 opening day at 15th Street and Pennsylvania Avenue NW as an exchange and brokerage business owned by William W. Corcoran, (George W. Riggs became a partner four years later,) the bank has been Washington's largest financial institution.

The names of the bank's top management over the decades -- Corcoran, Riggs, Glover, Fleming -- still color the geography, business and cultural institutions of metropolitan Washington. The bank itself has had both presidents and administrations among its customers -- Abraham Lincoln and Jefferson Davis had accounts there, and Riggs financed the Mexican war and put up the $7.2 million in gold paid to Russia to purchase Alaska.

However shocking Allbritton's takeover bid may have been to the directors and managers of this historic banking house and throughout the area's business community, it is just the most dramatic development in what is becoming a wholesale revolution in Washington banking.

Change is inevitable because the entire financiaal industry is being restructured across the country, with thrift institutions competing for checking account business as of Jan. 1 and creating a new marketing environment for banking-type services. Retailers and stock brokers also are seeking some of the bankers' traditional business. Volatile and record-high interest rates have added to the thrill of being a banker, whose daily work hours no longer begin at 9 a.m. and end at 3 p.m.

To these broader industry challenges in Washington is added the element of major management or ownership change at some of the key institutions. A new younger generation of Washington bank leadership is being installed. "It's anything but quiet," noted Dean Witter Reynolds Vice President Leslie Silverstone last week. In addition to Allbritton's recent acquisition of 15 percent of Riggs stock and his $43 million cash bid for more, these are among the key developments in recent days and months:

At American Security Corp., the next-door neighbor of Riggs which owns the area's second-largest bank, former Citibank executive Carleton Stewart was dismissed as chairman and replaced by W. Jarvis Moody, long the bank's president and a man deeply involved in Washington life.

Last week, The Washington Post revealed that ASC director A. James Clark, president of the hugely successful George Hyman Construction Co. here, had become the largest individual American Security stockholder by adding 100,000 shares and bringing his interest to 194,000 or 6 percent. A second local investor, not a director but described and "friendly" to American Security management, purchased another 100,000 shares.

Thus 200,000 shares of ASC gathered from several investors who wanted to sell have been consolidated in a way that means Moody and other officers can rest more soundly, since all area bankers now are wary of possible takeover situations.

Although Clark downplayed any new motivation for the recent $3.9 million stock purchase, (he had been accumulating stock over the years), analysts noted that Allbritton's bid had stimulated interest in ASC. Said Ryan: "When a large block of stock comes on the market, it's in the best interest of management for it to be in friendly hands."

The metropolitan area's third-largest banking firm is the target of a takeover bid by Middle East investors. Financial General Bankshares Inc., whose major properties are the First American Banks in Washington, Maryland and Virginia, has a unique interstate status here that is possible because banks in all jurisdictions were open before federal law prohibited new interstate retail banking operations.

The Federal Reserve Board had "accepted for filing" a bank holding company application from the Middle East group -- which means that all the papers are in order and unless there is some major problem or negative policy decision, the Middle East team should have a central bank approval by the spring. The deal could go through next summer.

Spokesmen for the investors, who include Kamal Adham, former head of Saudi Arabia's intelligence agency, say they are seeking a prestigious American banker to run Financial General and they have been talking to such individuals. Legal maneuvers to stop the deal were cleared up last week when a class action was dismissed. The current Financial General president, J. William Middendorf II, reportedly is President Reagan's choice to head the Export-Import Bank.

Maryland bank regulators, who had held up approval on the grounds that a bank in the state had not asked to be taken over, gave in after the bank asked. One banker said to be in the running for the top post is in the current Financial General family: First American of Virginia President Milton Drewer, who is making of the largest Northern Virginia bank not only a consumer-minded institution but also a major business and commercial bank for the growing enterprises on his side of the Potomac.

National Bank of Washington, the oldest and third-largest in D.C., has a new chairman, a new president and a new set of rules about lending practices in the wake of last year's federal and bank investigations into some questionable loans to directors and friends. With a majority of stock now owned by the United Mine Workers union, NBW is considered a possible candidate for acquisition by other investors.

Luther Hodges Jr., the new NBW chairman and former deputy commerce secretary, has an option to buy 12,500 shares of NBW at $22 apiece; the stock, which traded down to about $21 last year, was just under $40 a share last week. In recent weeks Hodges has launched the most agressive marketing campaign among big city banks for consumer business and helped pick up a batch of new directors and advisers from throughout the world of Washington, as he seeks to restore confidence in and profitability of the bank.

There has been a spate of announcements by Washington-based banks that they plan to form holding companies, a broader form of corporate structure that would permit establishment of related businesses and also allow separate banks to be set up across state lines if the government decides to allow interstate banking, possibly in the D.C. area as a test case.

Chairmen Joseph Riley at NS&T Bank, who has succeeded the retired Douglas Smith; Hodges at NBW; Vincent C. Burke Jr. at Riggs and Donald Menafee of Madison National are among chiefs who have started planning for holding companies, although Allbritton is opposed to the particular plan of Riggs management and has other ideas.

Smaller banks in D.C. are being sought and sold like souvenirs, as investors apparently are willing to gamble that an outside bank would like the city branches if and when interstate banking is approved.

Robert Tardio, chairman of Suburban Bancorporation, the largest banking firm in the Maryland suburbs, cautions that it may be cheaper in the end for outside banks such as his to open their own branches in Washington than to buy small D.C. banks at high premiums.

Tradio's banking firm is continuing to expand throughout Maryland, and he hired a former top First American official, "Bud" Manderfield, as Suburban's second-in-command to gear up for the new competitive race.

At Riggs, the focus remains on the Allbritton situation for the moment. Directors of the bank are on record as opposed to any investor owning more than 15 percent of a bank that has sought to maintain and improve ties to the local community while at the same time taking advantage of its natural position as the biggest Washington bank to become a significant factor in international finance.

Apparently, however, these individuals and their relatives or friends do not control enough of the bank's stock to block Allbritton's surprise bid to buy at least 600,000 shares at $67.50 apiece and thus raise his interest in the bank to 35 percent.